We propose using two-dimensional graphene derivatives, in particular fluorographene (FG), as a medium for light-harvesting and energy transport. Although pure FG has a large energy gap and hence does not allow light harvesting and transport of corresponding excitation energy, one can expect appearance of local excitations in FG with defects. Inspired by photosynthetic light-harvesting, we demonstrated treating defects in FG – regions where fluorine atoms are removed from the material (graphene isles) – as quasi-molecules between which there is no electron transfer. These impurities in fact play the role of natural pigments in photosynthetic antennae which can be modelled as Frenkel excitons. By quantum chemical calculations, we confirmed the localization of transition densities between electronic ground and first excited states on the region of two types of defects in FG: perylene-like and anthanthrene-like defects, which have transition energies within the energy gap of FG. Furthermore, we examined excited state properties, stability and interaction of these defects, which led us then to employ them as the building blocks of a hypothetical antenna with desired geometry. We construct several model antennae and obtain the energy transfer rates for a reasonable range of system-environment coupling strengths, which would result in high quantum yields in presence of expected losses.

Ref: V. Sláma, S. Rajabi, T. Mančal, arXiv:1801.08509.